It is well-known in the art to provide a printing assembly wherein a recording medium is provided and step-wise advanced over a print surface in a medium transport direction. A print head provides a swath of a recording substance image-wise on the recording medium. Then, after a next stepping of the recording medium, an adjacent swath is provided. Swaths are positioned relative to each other as accurate as possible such to prevent that banding due to misalignment of adjacent swaths becomes visible.
Accurate positioning of adjacent swaths requires accurate control of the position of the recording medium after each step-wise advancement and accurate control of the print head position relative to the recording medium.
In another, well-known embodiment, the print head is arranged on a print head carriage. The print head carriage is arranged to scan over the recording medium in a scanning direction that is substantially perpendicular to the medium transport direction. Accurate control of the print head position relative to the recording medium and in particular relative to a previous swath becomes more challenging.
In a known embodiment, the print head is a stationary page-wide print head (i.e. a print head extending over the full width of a web of recording medium). In such embodiment the position control of the print head is relatively simple. Therefore, it known to arrange the print head rotatably such that a rotational error of the web may be compensated by rotating the page-wide print head. Similarly, it is known to rotate a support beam of a scanning print head to compensate for a stationary arranged recording substrate such to have a scanning direction of the print head corresponding to an orientation of the recording substrate.
With an increasing demand for high productivity and a broad recording medium range with different media types having different properties, also with respect to advancing and positioning, the requirements on the printing assembly are still increasing. In particular, in a printing assembly for printing on relatively wide (e.g. 64 inch (1.6 m) or wider), it is relatively expensive to provide for a page-wide print head or array of aligned print heads, while the positional and rotational errors exponentially increase due to flexibility in the recording medium or misalignment of guiding rollers.
It is therefore an object of the present invention to provide a printing assembly for printing on a web of recording medium and a corresponding printing method that are suitable to meet the demand for a versatile and productive printing assembly for printing on a wide-format web of recording medium.